And charles e



(No Model.)

G. W. OOY.

TELEPHONE EXCHANGE SYSTEM.

Patented Sept. 19, 1882.

JATTESTI lwvEgTuq: %W 1W v f UNITED STATES PATENT OFFICE.

GEORGE TV. OOY, ()F MILFORD, CONNECTICUT, ASSIGNOR OF TWOTHIRDS TO JAMES G. SMITH, OF HAOKENSAOK, NEW JERSEY, AND CHARLES E. BUELL, OF WASHINGTON, DISTRICT OF COLUMBIA.

TELEPHONE-EXCHANGE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 264,631, dated September 19, 1852.

Application filed February 23, 1882. (No model.)

To all whom it may concewu. or arranged to be connected to the trunk-line,

Be it known that I, GEO. W. Gov, acitizen or it may be, so far as the latter objects are of the United States,residing at Milford,in the concerned, apparatus arranged to be connectcounty ofNew Haven and State ofGonnecticut, ed to the .wire O, in which case the ordinary 5 have invented certain new and useful Improvesignaling and communicatingapparatus of the ments in Telephone Exchange Systems, of exchange might be brought into play. which the following is a specification. Any suitable signaling and communicating My invention consists of certain novel comapparatus may be employed, and any desired binations of switching and signaling apparaconstruction of switches for making the re- 10 tus for employment with telephone systems in quired electrical connections may be used. I

which distant central stations are connected have herein shown one arrangement of appaby trunk-lines composed of complete metallic ratus that may be employed for this purpose, circuits arranged to form aconnection between and which also possesses the advantage that the secondary coils of induction apparatus at the induction-coil may be removed from the [5 two central stations when a subscriber of one circuit, but that the line cannot, through negstation is conversing with a subscriber of the lect in restoring the switches to their proper other. position, be left in an inoperative condition,

The nature of my invention will be hereineither for sending or receiving calls.

after described, and the invention will be K represents a spring-key or other circuit 20 specified in the claims. shiftingapparatus for changing theline-circuit Figure 1 is a diagram illustrating my invento a loop containing a signaling-battery, M B, tion. Fig.2 illustrates a construction of inor equivalent device. duction-coil that I sometimes employ. S is a switch for removing the induction ap- A and B represent the switch-boards of two paratus from or introducing it into the line- 25 distant telephone-exchange systems of any circuit.

construction; a a a a, subscribers wires of G and H are signal-bells or annunciators, those systems; and b I) Z) I), 850., the wires by the one, G, in the normal line-circuit and the which the circuits of the subscribers are comother, H, in a circuit leading to the induction pleted in any suitable manner, either by passapparatus. 3;) ing to earth or toa common return-wire, or by lf desired, bell H only maybe used, or said independent wires for the various lines. bell may be located in the trunk-line at some (3 represents a wire at each station, leading point outside of the switch apparatus. to the primary of an induction-coil, I, or to a S is a switch whereby the telephone appawire of the same size as and parallel to the ratus M, of anydesired construction, may be 35 wire in the induction-coil, which is designed interposed in the trunk-line when it is desired to form a portion of the trunk-line circuit, or to communicate orally between the exchanges. 8

' to any other device adapted toinduce currents The operation is as follows: Normally the in another wire or circuit. switches S are upon the studs connected to E represents the earth-plate or equivalent bell G, and switches S on the stud completing 4o connection of said wire 0, and F a bar, strip, the line-circuit outside of the telephone appaor plate, or other suitable device bywhich any ratus M, and keys or switches K are against one of the lines of the exchange system may their upper stops. The circuit of line 10 is be connected to the wire 0. Themetallic cirthen through upper stop of K, switch S, and cuit connecting the distant exchanges is repbell G, battery M B, the induction apparatus I 5 resented by the figure 10. Suitable apparatus and telephone apparatus M being outof circuit.

for connecting said line through theinduction- If a subscriber in exchange A desires to com- 5 coil, and for receiving and sending calls and municate with a subscriber at B, the operator conversing over said line, is provided at each at A depresses key K, thus introducing main exchange. Said apparatus may be located in battery M B into the circuit and cutting out the switch S, and, if the switch be connected to the induction apparatus,the latter also, thus causing the bell G at B to ring. By turning switches S at both exchanges so as to intro duce the apparatus M the operators at both stations may communicate orally. Operator at B having learned the subscriber wanted, connects that subscribers line with the wire 0, leading through one wire of the induction coil or apparatus, and throws the switch S so as to introduce the other and parallel wire of the induction apparatus into the trunk-line circuit. Operator at A connects the line of the subscriber asking for the connection and the trunk-line in a similar way with the induction apparatus at A. The telephonic vibrations or pulsations from subscriheis line on A will then by circulatingthrough the induction apparatus 1 at A induce corresponding pulsations in the line circuit 10, which, by circulating also through the induction apparatus I at B, induce pulsations in the wire (3 and the connected subscribers line of exchange B, so that conversation may take place between the subscribers of the distant exchange.

If after conversation is finished either operator should neglect to restore his switch S to normal position, calls would be indicated in an annunciator or bell, H. It would also be possible to introduce the battery M B into the circuit, so as to call another exchange office, while, moreover, the operation of the key K will cut out the induction-coil I when the battery is introd need.

If induction-coils of ordinary construction be employed, I prefer to make what is known as the secondary coil a portion of the trunkline circuit, and to connect the coarser or primary wire to the wire 0. I may, however, employ a coil in which both wires are of the same size and wound side by side throughout. Such a construction is indicated in Fig. 2.

Myinvention is not confined to any particular construction of switching or signaling apparatus; nor, as I before mentioned, to any p articular kind of induction apparatus, it being only necessary, so far as the latter element of the invention is concerned, that it should be of such a construction that the passage of a current in one portion thereof will induce a current in the other portion thereof.

It is obvious that any number of trunk-lincs similarly connected to the exchange apparatus and provided with the apparatus described changes may be connected to the same metallic circuit.

What I claim as my invention is 1. The combination, substantially as described, of two or more distant telephone exchanges, a complete metallic circuit connecting said exchanges, an induction-coil at each exchange, provided with means for introducing it into the metallic circuit, and a signaling-key and annunciator in said circuit at each station.

2. The combination, substantially as described, of the telephone-exchange switchboard provided with a strip common to the subscribers lines, induction apparatus I, one coil of which is permanently connected to said strip, and a metallic-circuit wire leading to another station and arranged to be connected to the other coil of the induction apparatus.

3. The combination, substantially as de' scribed, of two or more exchange-switches, an induction-coil at each switch, arranged to form a portion of a metallic circuit connecting said switches, and circuit-shitting apparatus or key K for alternately introducing a generator into and removing it from said metallic circuit.

4. The combination, substantially as described, of two or more exchange-switches, an induction apparatus at each switch, one coil of which is connected to the exchange switchboard, a complete metallic circuit connecting the exchange-switches, and a switch in the metallic circuit at each exchange for introducing one coil of the induction apparatus into and withdrawing it from the metallic circuit,

5. The combination, substantially as described, of the induction apparatus located at the telephone exchange, the trunk-telephone line, a switch for throwing the induction apparatus into the main-line circuit, a main battery, and a switch for connecting the battery to a loop around both the induction apparatus and the induction apparatus switch.

6. The combination, substantially as described, of the trunk-telephone line, the induction apparatus, the two-p.oint switch S, with connections, as described, the main battery M B, and the key K, all connected in the man: ncr shown and described.

GEORGE W. COY.

\Vitnesses:

H. O. TOWNSEND, THOS. TOOMEY. 

